CURRENT DIRECTION DETERMINING CIRCUIT, AND SWITCHING REGULATOR HAVING THE SAME

摘要

A current direction determining circuit wherein the power loss of a switching regulator can be suppressed and the circuit size can be reduced. The current direction determining circuit (16) comprises a monitor transistor (20) whose control and output terminals are respectively connected to the control and output terminals of a ground-side output transistor (12); an impedance element (21) having one of its ends connected to the input terminal of the monitor transistor (20) and having the other end grounded; first and second constant current sources (22,23); a diode-connected reference transistor (24) inserted between the first constant current source (22) and the ground potential; and a sense transistor (25) inserted between the second constant current source (23) and the impedance element (21) and having its control terminal connected to the control terminal of the reference transistor (24).